The invention relates to a liquid-cooling circulation system for power and working-machines (especially internal combustion engines) with an air-separating tank which lies in a by-pass vent line that extends from a high point in the radiator inflow fill line.
The air separating tank is provided at its high point with a fill inlet having a fill-in opening, a closure cover, and a line connected with a bottom area of an atmospheric expansion tank through excess pressure and vacuum relief valves each located in the closure cover. The excess pressure valve limits the pressure in the air-separating tank through a control line in the radiator inflow. The air-separating tank is arranged at the high point of the radiator inflow. The fill inlet includes connecting openings to the high points both of the radiator inflow and the air separating tank. The closure cover, in addition to closing the fill opening of the fill inlet, also closes the connecting openings with respect to one another. A throttle line connection is extended, as part of the by-pass vent line, from the high point of the radiator inflow to the bottom-near area of the air-separating tank.
The closure cover includes a direct control line between the connection opening of fill inlet and radiator inflow on one hand and the excess pressure valve limiting the pressure in the radiator inflow on the other. The excess pressure relief valve has an adjusting motor control diaphragm at the radiator inflow. A temperature-controlled venting valve is arranged in the line connection from the high point of the air-separating tank to the expansion tank and has a closing-shifting-temperature which lies below the thermostatically controlled normal operating temperature of the cooling medium. This ensures a conditioned cooling medium-pressure curve and cavitation free operation at the suction side of the cooling medium pump.
Furthermore, the invention relates to a liquid-cooling circulation system for power and working machines (especially internal combustion engines) with a fill inlet and a fill cover at a high point in the radiator inflow. An expansion tank is provided with a fill cover and an expansion and reservoir volume areas. Excess pressure and vacuum valves are provided in one of the two fill covers and there is a line extending from the high point of the fill inlet to the bottom area of the expansion tank. An air-separating tank is arranged at the fill inlet of the radiator inflow, which is located in a vent by-pass line that extends from a high point of the radiator inflow to the radiator return flow, and has a cross section throttle place between the radiator inflow and the air-separating tank. A high point of the vent line is connected to the line-connection from the fill inlet to the bottom area of the expansion tank.
Still further the invention contemplates having an air-separating tank which lies in a by-pass vent line extending from a high point in the radiator inflow to the radiator return flow. The high point includes a fill inlet with a fill-in opening and closure cover and is connected by an excess pressure and a vacuum valve (located in the closure cover) with the bottom area of an atmospheric expansion tank.
The vent line includes a throttling place ahead of the discharge into the air-separating tank. A temperature-controlled vent valve is arranged in the line connection from the high point of the air-separating tank to the expansion tank. Its actuating temperature lies below the thermostatically regulated normal-operating-temperature of the cooling medium for ensuring a pressure curve at the suction side of the cooling medium pump that provides cavitation-free operation thereof.
The invention also contemplates an atmospheric expansion tank which is series-connected to atmosphere, and wherein downstream of the excess pressure, vacuum and vent-valves the temperature-controlled vent valve is constructed at the same time as vacuum valve in the closure cover. This temperature-controlled vent valve has a valve body with a thermo-snap-spring that cooperates with a sealing ring acting as valve seat. The valve is acted upon by a spring and/or a float in the direction towards the sealing ring. The spring, float, valve body and sealing ring are arranged sequentially and coaxially, vertically one above the other in the valve body of the excess pressure valve. The temperature vent valve has a valve opening arranged parallel to the valve opening of the pressure valve.
The invention also contemplates having a heating by-pass circulation which branches off from a high-lying cooling jacket outlet and contains an electrical auxiliary pump and a heating arrangement for a vehicle. Here the auxiliary pump is adapted to be energized in dependence on a cooling medium and/or component minimum temperature existing in the engine.
A shifting valve directs the cooling medium leaving the engine cooling jacket to by-pass the heating arrangement and to be fed back into the cooling jacket through an inlet disposes opposite the outlet when the engine is turned off. The flow of the cooling medium through the cylinder head cooling jacket of internal combustion engines is so dimensioned that, a vapor bubble-detaching and-condensing intensity is assured at hot places.
In a known arrangement according to the DE-OS 32 267 508, corresponding to European Pat. No. 0-100 917, Japanese Pat. No. 59-23029 and U.S. Pat. No. 4,510,893, the air separating tank is connected to the suction side of the cooling medium pump by way of a return suction line which is used as a filling line. During filling, the cooling medium flows from the bottom area of the air-separating tank, by way of the return suction line to the low-lying cooling medium pump and from its bottom side into the cooling jacket of the engine. As the direct connection between cooling medium pump and return-water tank of the radiator is closed by a thermostat arranged in the radiator return line during the filling of a cold engine, the cooling medium can initially only flow into the cooling jacket and fill the same. However, this filling operation is delayed by the thermostat arrangements at the cooling jacket outlet and by the narrow interior cross section of the vent line from the radiator inlet to the fill inlet. This is true since the air to be displaced must escape exclusively out of the cooling jacket and out of the radiator. The low fill-velocity provided thereby not only increases the necessary filling time, but also the residual air-volume portions that remain in the cooling jacket and in other line sections. The cooling medium finally reaches the radiator only after the cooling jacket is completely filled. This is by way of the inflow line as a result of which, the filling velocity is further decreased and remaining residual air-volume portions are maintained in the radiator. An additional lengthy venting operation during running engine and removed closure cover is therefore necessary. Residual air which continues to remain in the cooling circulation system can be separated into the atmosphere by way of the expansion tank acting as air lock (after its precipitation out of the cooling medium solution at high temperature and after its collection at the excess pressure valves), when the excess pressure valve-opening values are exceeded. The advantages of an air-free cooling circulation system, such as steeper pressure build-up with increasing cooling medium temperature and reduced corrosion danger for the cooling circulation system components and the cooling medium itself cannot be obtained by reason of the extensive degassing. This is hardly effective, or at best considerably time-delayed, after numerous warm/cold cycles of the engine. Additionally, after a lengthy venting operation, no adequate pressure build-up of the cooling medium from the thermal-expansion thereof is available. By reason of the thermal-expansion of the cooling medium, which takes place prior to the closing of the closure cover without pressure build-up, the boiling limit (the pump cavitation limit) is then rapidly reached during the further rise of the operating temperature and an engine-overheating directly following operation at high load is unavoidable.
By contrast, an excess pressure (super-elevated in relation to relative low cooling medium temperature) occurs in the range where opening of the excess pressure valves occurs in the cooling circulation system of internal combustion engines. Here combustion gas-leakages penetrate into the cooling circulation system at high load and generally at low starting temperatures (especially at minus degrees) which are not adequately reduced during the cooling off of the engine in operating pauses. Additionally, the combustion gas-volume portions remaining in the cooling circulation system act destructively on the cooling medium additives as well as causing corrosion of the interior of the cooling circulation system components.
Finally, during the rapid turning off of the engine from high load, a strong local overheating of the cooling medium frequently occurs at hot spots in the cooling jacket. This causes corresponding high pressure vapor bubbles which may lead to strongly super-elevated pressure in the entire cooling circulation system. The consequence of this is: cooling medium discharge by way of the excess pressure valve; the overflow of the expansion tank; and the creation of insulating deposits in the cooling medium, especially water scale which attacks the system precisely at the hot places.
The task of the instant invention is to overcome the aforementioned described disadvantages within the range of the operating conditions-filling, venting, degassing, pump-cavitation, overheating, turn-off-after-heating, unnecessarily super-elevated progress of the cooling medium pressure in relation to the progress of the cooling medium temperature at low start, ambient temperatures and during penetration of combustion gases into the cooling circulation system. Also it is desired to reduce structural expenditure, costs, weight, component multiplicity, and incorrect operating possibilities. Furthermore, over-all dimensionings of cooling circulation components and of the cooling output, which heretofore have been standard of the compensation schemes used, are avoided.
The invention attains this in a surprisingly advantageous manner by having the air-separating tank arranged at the high point of the radiator inflow and the fill inlet include connecting openings to the high points both of the radiator inflow and the air separating tank. A closure cover, in addition to closing the fill opening of the fill inlet also closes the connecting openings with respect to one another.
A throttle line connection in a by-pass vent line is extended from the high point of the radiator inflow to the bottom-near area of the air-separating tank. The closure cover includes a direct control line between the connection opening of fill inlet (radiator inflow) and an adjusting motor of the excess pressure valve that limits the pressure in the radiator inflow.
A temperature-controlled venting valve is arranged in the line connection from the high point of the air-separating tank to the expansion tank and has a closing-shifting-temperature which lies below the thermostatically controlled normal operating temperature of cooling medium to provide the conditioned cooling medium-pressure curve at the suction side of the cooling medium pump for the cavitation-free operation thereof.
The filling of the cooling jacket and of the radiator is accelerated by such an assemblage. Also the residual air-inclusion is reduced because the cooling medium can flow from the fill-in opening equally and rapidly into the cooling jacket and into the radiator and the air can flow directly out in a counter-flow. Owing to the high cooling medium flow velocity, the residual air bubbles are taken along and only small residual air portions remain in the various cooling medium carrying lines and hollow spaces of the cooling circulation system. During the next operation of the engine, remaining residual components are flushed rapidly out of the inflow-high point into the air-separating tank by way of the vent line discharging out of the same. With arrangement of this discharge near the engine, a low-lying radiator arrangement for strongly dropping passenger motor vehicle front ends is thereby possible. Here the radiator in-flow drops off toward the radiator and an additional reduction of the cooling medium volume and a reduced warm-up time is thereby reached. This applies to an increased extent, compared to a normal connection of the vent line at the high point of cross-flow radiator inflow water tank.
At the same time venting, degassing and system pressure build-up as a function of temperature and rotational speed is improved by the temperature-controlled vent valve. Likewise cooling circulation pressure, super-elevated by reason of combustion gas leakages, is again reduced during cooling-off phases. The line connection (from the air-separating tank to the expansion tank) which is opened by the thermo-valve at low operating temperature, further enables a very simple venting operation after filling. With a closed closure cover, a continuous cooling medium residual air-outflow to the expansion tank, and cooling medium inflow into the air-separating tank is achieved during major engine rotational speed changes. This results from the rise of the pump-suction pressure at rotational speed reductions and the drop thereof at rotational speed increases.
In conjuction with a filling level indicator in the air-separating tank that includes a float chamber separate from the air-separating tank, which is line-connected at the bottom with the air separating tank and at the top with the valve chamber of the closure cover, continuing venting can occur at ever-increasing rotational speeds. This is true when the air-separating tank is arranged at the fill inlet of the radiator inflow, which in turn is located in a vent by-pass line from a high point of the radiator inflow to the radiator return flow and which has a cross section throttle place between radiator inflow and air-separating tank, and wherein its high point is connected to the line-connection from the fill inlet to the bottom area of the expansion tank. By having the closing temperature of the venting valve matched to the pressure build-up, dependent on the cooling circulation elasticity (hose-length and elasticity), or coolant temperature and/or pump rotational speed, avoids unnecessarily high cooling circulation system excess pressure values at relatively low cooling medium temperature values. It also assures an adequate spacing of the pump suction pressure curve with regard to the curve of the pump cavitation limit. A high pump feed output (as a result of high engine rotational speed in the shifting point of the thermo-valve) leads to a correspondingly higher starting pressure for the pressure build-up from the thermal expansion of the cooling medium during further temperature increase. This is due to the atmospheric pump suction pressure being strongly decreased in relation to the average cooling circulation system (excess pressure), but held constant by reason of the opened vent valve. As a result thereof, the chance of pump cavitation is additionally decreased during operation with relatively high rotational speeds.
By having all control elements located in the closure cover one obtains a compact cost and weight-favoable construction that facilitates servicing and repair.
By having the fill inlet terminate directly in a high point of the radiator inflow and the air-separating tank concentrically surrounding the fill inlet with a high point thereof connected to the valves in the closure cover by way of the connecting opening thereof and by having the radiator inflow pass through the air-separating tank within the area of the termination of the fill inlet, one obtains a particularly compact spatial coordination of the air-separating tank relative to the radiator inflow and to the filling inlet.
When the fill inlet and the radiator inflow are line-connected laterally, mutually intersect and/or extend through one another, and when the air-separating tank adjoins the fill inlet and the inflow line in the downward direction, one can obtain a compact construction. This is true if a hollow cylindrical insert, tightly adjoining the closure cover and the air-separating tank, is arranged in the connecting, intersecting and/or penetrating area of fill inlet and radiator inflow and when the interior space of the insert extends the air-separating tank upwardly to the bottom side of the closure cover and is connected by way of an opening in the bottom side of the closure cover and when the valves are located in the closure cover. Also the vent by-pass line should terminate in the interior space of the insert from the high point of the radiator inflow (by way of the unthrottled line-connection) when a throttle extends out of the bottom side of the closure cover through the insert and into the air-separating tank.
The insert is secured at the closure cover and contains a vent line section which concentrically adjoins an outlet opening of the closure cover and together with the interior space of the insert forms an air-return flow lock. This produces a further reduced structural expenditure because the by-pass-line portion in the air-separating tank is constructed completely in the closure cover and in the insert secured thereon. The insert thereby separates the air-separating tank from the radiator inflow and opens up the connection with a removed closure cover so that a simultaneous rapid filling and venting of the engine cooling jacket, radiator, and air-separating tank can take place.
Having the air-separating tank provided with a relatively large cross section hose-connecting nipple and a hose section adjoining the same, allows for volume expansion of the air-separating tank, as a result of which the dimensions and structural expenditure thereof are reduced.
By providing a cooling medium-level indicator in the air-separating tank, a safe filling level monitoring of an excess pressure cooling circulation system and a warning indication for operationally safe sufficient cooling medium content is possible. This is true because temperature-conditioned volume changes of the cooling medium already trigger a warning with a cold cooling circulation system, when the cooling medium warms-up during operation and exceeds the indicating level. Additionally, the filling level warning indication thereby forms a monitoring indication during the venting of the cooling circulation system after a new filling or refilling. More particularly, the pumping out of the residual air (by way of the expansion tank into the atmosphere) is possible by the simple measure of an operation of the engine with strong rotational speed change having an open line connection between the air-separating tank and expansion tank. This actuates, with dropping residual air volumes, a customary level warning light which is displaced continuously toward higher rotational speed and with unitary or separate construction of the level indicator housing with respect to the air-separating tank.
By having the cooling medium level transmitter include a float chamber that is separate from the air-separating tank and which is line-connected at the bottom with the air separating tank and at the top with the valve chamber of the closure cover, also provides a desired basic arrangement of the air-separating tank with fill inlet and filling cover at the high point of the radiator inflow. As a result, a large part of the advantages are achieved independently of the arrangement and construction of the excess pressure, vacuum/and vent-valves. Namely, advantageous filling and venting as well as rapid warm-up can be obtained. The valves can thereby be selected of any known or hereinabove proposed construction and arrangement, such as interconnection at the air-separating tank, at the expansion tank, or at both in series connection. With the two last-mentioned arrangements, an expansion tank with air expansion volume is required.
By having an excess pressure valve in the closure cover that is controlled by way of a control line by pressure in the reduction inflow, an additional control of an excess pressure valve by the pressure in the radiator inflow for the direct limiting of the pressure valve acting upon the radiator is possible. This is true when the valves are located in the radiator return flow and a fill inlet and a fill cover in the fill-in opening thereof at a high point in the radiator inflow; with an expansion tank having a fill-in cover, expansion and reservoir volume; with an excess pressure and vacuum valves in one of the fill covers; and with a line connection from the high point of the fill inlet to the bottom area of the expansion tank.
When a temperature-controlled vent valve with a closing-shifting-temperature is arranged in the line connection from the high point of the air-separating tank to the expansion tank and when the temperature lies below the thermostatically regulated normal-operating-temperature of the cooling medium, the pressure curve at the suction side of the cooling medium will provide for a cavitation-free pump operation. Apart from a slight additional structural expenditure and weight, this construction ensures the other functional advantages of the features of the invention previously indicated above. This is especially true in conjunction with an additional fill cover arranged in a known manner at the high point of the radiator inflow.
By having an atmospheric expansion tank series-connected to atmosphere downstream of excess pressure, vacuum and vent-valves; with the temperature-controlled vent valve constructed as a vacuum valve in the closure cover and with a valve body having a thermo-snap-spring that cooperates with a sealing ring as valve seat and valve opening and which is acted upon by a spring and/or a float in the direction toward the sealing ring; with the spring, float and sealing ring arranged sequentially and coaxially vertically one above the other in the valve body of the excess pressure valve; and with a valve opening arranged parallel to the valve opening thereof, one obtains ease of servicing and repair. Examination and/or exchange of the closure cover as a unit helps in this regard. Individual components which have long proved themselves in the motor vehicle technology are thereby used. The coordination of the components is facilitated because the snap spring is acted upon by the cooling medium temperature only after complete air discharge, so that the venting is favored by the cooling medium (even beyond reaching the closing-shifting temperature). A float in lieu of a closing spring is thus required only in particularly difficult venting conditions. The closed vent valve is assisted in its sealing function with increasing cooling medium pressure, because the thermo-snap-spring is thereby pressed more and more against the sealing ring.
By having a further vent line which starts from the high point of the radiator outlet water tank and terminates in the air-separating tank and which vent line includes at least one air/gas/temperature controlled vent/degassing valve which opens upon the pressure of air and/or gas during a predetermined warm-up temperature of the cooling circulation system, also assists in the filling and venting of the residual air to the air-separating tank. The tank, during filling, remains in the return flow of water to the cross flow radiators. However, a through-flow of cold cooling medium is prevented in the normal warm-up operation and thus an undesirable influence on the warm-up period is avoided. On the other hand, owing to the opening of the vent valve after the warm-up (at a cooling medium temperature lying above the ambient temperature, 60.degree. in the return flow-water tank), combustion gas leakages, as well as residual air-volume parts (preferredly collecting therein), are immediately conducted away into the air-separating tank. They quickly flow out of the same by operation of an excess pressure valve and the expansion tank into the atmosphere (when the excess pressure in the cooling circulation system reaches the opening values of the excess pressure valve). Any leakage volume parts which possibly remain, are discharged (during the cooling-off of the cooling circulation system below the opening temperature of the vent valve) through the expansion tank and at the same time the cooling circulation system is thereby kept constantly at atmospheric pressure as long as the closing temperature of this temperature-controlled valve has not been reached. Vacuum in the cooling circulation system and penetration of air, conditioned thereby, (for example, by way of the seal of the cooling medium pump) is thereby additionally precluded.
By also having the vent/-degassing valve include a float as closure device, a thermo-snap-spring as a valve body and an O-sealing ring as valve-seat in this sequence and coaxially vertically one above the other in a valve chamber, provides for a functionally and structurally particularly advantageous construction of the vent-/degassing valve. Here there is a reverse temperature control with opening instead of closing by way of the shifting temperature of the valve. In lieu of the float and customary closing spring, a separate ball or flapper vent valve can be used as is customary in cooling medium thermostat valves.
By having the connection of the control line at the radiator inflow as a suction-jet-pump-like construction, such that excess pressure in the radiator inflow rising with increasing engine rotational speed (cooling medium pump-feed output) is introduced into the control line, enables an inflow pressure control to maintain the excess pressure valve in the closure cover even with excess pressure in the inflow area increasing with the pump feed output. Such is also maintained without separately matching the pressure control to the necessary highest excess pressure opening value that is possible. At the same time, the excess pressure valve can be constructed with the same excess pressure opening value for the inflow and return flow area. This additionally favors reduced structural expenditures and the number of closure covers necessary for different engines.
By having a further excess pressure temperature-dependent valve connected in series between the air separating and expansion tanks and with a closing shifting-temperature that lies above the thermostatically controlled normal operating temperature of the cooling medium (by virtue of the fact that the excess pressure valves have matched opening values) a desired temperature control is obtained. This is true since the closing temperature of the further excess pressure valve occurs at the highest engine rotational speed and excess pressure at the pump inlet has a sufficient spacing with respect to the pump cavitation limit. At the highest projected operating temperature condition reached, this value lies above the boiling pressure which (after turning off the engine from high load) corresponds to the locally occurring highest projected cooling medium temperature. This keeps the cooling medium pressure at relatively low level during normal operation and when combustion gas leakage is introduction into the cooling medium. Only with simultaneous high operating load and surrounding temperature does a shifting take place to the then necessary higher cooling medium pressure by the additional temperature excess pressure valve. Unnecessary high excess pressure loads of the cooling circulation system by reason of combustion gas leakages are avoided thereby and a continuous discharge of these combustion gas volume parts out of the cooling circulation system is achieved.
By having a manually actuatable vent arrangement in the line connection between air-separating tank and expansion tank (which valve is opened by a vent screw or a vent rotational position of the closure cover) provides for a cooling circulation system venting under particularly different conditions that are normal beyond the shifting temperature of a thermo-valve. The venting operation also limits itself to an operation of the engine with strongly changing rotational speeds (e.g. short turn-off pauses), so as to permit eventual air bubble accumulations at the pump inlet to press to the pump pressure side.
By having the expansion tank include a connection for a temporary pressure gas feed (above its fill level) to be conducted to the cooling medium level feed through the line connection to the air-separating tank, or through the vacuum, vent, and/or thermo-valves, allows for a corresponding pressure build-up. This prevents safe pressure overload of the expansion tank. To safeguard the projected operating excess of the cooling circulation system during servicing and/or repair operations, the cooling circulation system is closed at such a high cooling medium temperature so that the necessary pressure build up is no longer possible from thermal expansion of the cooling medium. This construction is particularly useful in conjunction with the manually actuatable venting arrangement recited Supra.
By having the expansion tank constructed with a pressure-resistence (approximately up to the middle cooling circulation system-operating pressure) and with an excess pressure safety valve, the fill cover of the expansion tank is then constructed as excess pressure safety valve at the expansion tank. Here a connecting nipple for a removable overflow hose serves as connection for the pressure gas supply. Compared to known cooling circulation systems the pressure strength of the expansion tank, the fastening of the associated filling cover and the dimensions of the connecting nipple for the associated overflow hose are the only components whose strength has to be specifically provided for.
An incorrect handling during the servicing of the cooling circulation system is precluded by having the air-separating tank and the expansion tank (as well as the fill covers thereof), arranged directly adjacent one another and by having the fill cover of the expansion tank cover the air-separating tank in the cover's closed position. Here an unintentional discharge of the cooling circulation excess pressure, by inadvertent opening of the associated closure cover (in lieu of the filling cover for the atmospheric expansion tank) is precluded. The closure cover is thereby accessible only when the filling cover is opened and removed for refilling. A removal of the closure cover by servicing personnel is then no longer to be expected. This is especially true in conjunction with the corresponding customary warning labelling of the closure cover. The structural expenditure of this measure includes a slight increase for a filling cover which can have a form and favorable coloring for the engine space styling.
The build-up of an excess pressure reaching the excess pressure opening value of the excess pressure valve (during the after-heating of the cooling medium after turning off the engine from high operating load) is avoided by having the auxiliary pump engaged with the hot turn-off of the engine in dependence on a cooling medium and/or a minimum temperature. A shifting valve is actuated to direct cooling medium leaving the cooling jacket (in lieu of vehicle interior heating arrangements), back into the cooling jacket through an inlet disposed opposite the outlet. The flow of the cooling medium through the cooling jacket is so dimensioned that a vapor bubble-detaching and condensing intensity is assured at hot places. In vehicles with already present heating circulation, the excess heating can be disapated by use of an auxiliary pump with a shifting valve. Vapor bubbles forming at the hot places are continuously slushed away by the cooling medium flow produced by the heating circulation auxiliary pump and are again condensed rapidly in the remaining cooling medium. A volume increase of the cooling medium in the circulation system which otherwise occurs is minimized. This effects an excess pressure in the entire cooling circulation system corresponding to the local cooling medium temperature and the associated boiling pressure. An excess expulsion of cooling medium through the excess pressure valve into the expansion tank and after overflow thereof is thus precluded.
Individual features of the invention art already known among the state of the art from numerous printed publications. Applicants combination thereof is neither suggested from these printed publications nor can it be derived therefrom without inventive activity. In particular, reference is made to the service instructions 1984 for the passenger motor vehicle--model Nissan ZX 300--model series Z31--pages LC-8/-13 and /18; to the DE-PS Nos. 25 09 995 and 28 17 976; to the DE-GM No. 19 31 736; to the GB-PS No. 1 415 698; to the EP-PS No. 0 101 339 as well as to U.S. Pat. Nos. 2,195,266; 3,047,235; 3,285,004; 4,167,159 and 4,489,883.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.